Much of the desert areas, both valleys and mountains, found in arid and semi-arid regions of the United States and other parts of the world are covered by a thin coating of generally dark coloration commonly called "desert varnish". For example, in the Southern California and Arizona deserts, this varnish covers the majority of the coherent-stable rock surface including mountain ranges. In some areas of Southern California desert varnish has been reported to be formed in as little as twenty-five years after exposure of fresh rock. However, in other areas, such as Arizona, petroglyphs documented to have been formed four hundred to a thousand years ago by scraping away desert varnish coatings have not been covered by the re-establishment of the desert varnish. In Egypt desert varnish is barely perceptible on pyramids that have existed for more than 5,000 years.
In desert areas, man's activities, such as in the construction of dams, roads, preparation of sites for construction and other activities of a like nature have exposed large, unsightly areas of lightly colored glaring scarps of freshly exposed rock which are visible from great distances as unsightly anomalies on the desert landscape. The removal of the natural desert varnish in this fashion occurs in both urban and rural areas and is particularly objectionable in the highly visible mountain areas; for example, where large cuts and fills are made to accommodate building sites and major roadways.
Nature's timetable in restoring the desert varnish to the freshly exposed rock is much too long and in some cases extends over centuries. Therefore, a real and urgent need exists for means methods and products which can be used to restore the natural desert varnish or to cover the exposed areas with a suitable substance of manufacture which will at least engender or simulate desert varnish coated natural rock.
One prior art effort to realize a solution to this problem included shocking exposed rock with caustic solutions and thereafter painting the pre-treated rock with one or more metallic salts, preferably those of manganese and/or iron in the form of chlorides, sulfates and nitrates. While obtaining amelioration of the eyesores to a modest degree, this procedure was environmentally unfriendly, labor intensive and prone to washing if subjected to inclement weather during the cycle prescribed. Thus, the procedure was sometimes ineffectual in unequivocally obtaining the substantially permanent uniform visual repair desired.
Accordingly, a need still exists for providing means and methods to restore disturbed rock beds and mountainsides to a natural look in an environmentally friendly, economically viable manner. It is toward the satisfaction of these needs that the present invention is directed.